The invention refers to an interior paneling component for motor vehicles, in particular dashboard-, side-, column- or door paneling, with an integrated airbag cover and a method and a device for their manufacture.
Components for interior paneling of motor vehicles today normally serve also always to cover up air bag modules. In order to realize a deployment of the air bag without any problems in case of an accident, the components are provided with air bag covers which easily open up upon deployment of the air bag, and thus support the inflation of the air bag into the interior of the vehicle. A frictionless and secure function of the air bag is possible only when the air bag cover functions in such a way that it controls the unfolding of the air bag. Thus, the air bag cover must be provided with a hinge which facilitates the opening of the cover. Furthermore, it has to be made sure that the cover, upon opening, does not get uncontrollably destroyed thereby hurling splinters throughout the interior of the vehicle and thus endangering the passengers in the vehicle. In order to avoid such, the air bag cover is normally provided with a splinter protection. This function is oftentimes carried out by separate systems such as for example, by sheet metal or textiles.
The air bag hinge usually also has the function to reduce surplus energies when fulfilling the protective function upon the fast and explosive deployment of the air bag, which requires a correspondingly large amount of energy. The explosive deployment of the airbag can lead to severe damage to the support part, leading to sharp edges that can cause severe injuries to the vehicle passengers and should be prevented by absorbing a portion of the surplus energy already upon opening of the air bag cover and thereby reducing the potential for injury to the passengers of the vehicle.
From the prior art diverse means are known for absorbing a portion of the energy generated upon the opening of the air bag cover, which all have the purpose of providing resistance to the airbag upon deployment in the area of the air bag cover, such that a portion of the energy is used upon overcoming the resistance. The air bag cover itself is normally constructed from several plastic layers, which provide the cover with sufficient elasticity and firmness and wherein normally different plastic materials are utilized for each layer whose properties are combined in order to provide sufficient resistance to the unfolding air bag. Oftentimes, the cover is also constructed as a hybrid-type, with reinforcement materials that are built into the plastic material and to realize the necessary firmness for the cover. Steel sheets and textiles can, for example, be utilized as composite materials.
A purposeful opening of the air bag cover is also realized in that the area of the air bag cover additionally is provided with pre-determined rupture lines or weakened areas whose configuration on the one hand controls the force required for breaking open the cover, and on the other hand, by their spatial arrangement controls the targeted and clean breaking of the cover.
From the afore-described it is easily seen that a functional configuration of the air bag cover is associated with relatively high expenditure of work and cost.
Since no such high expenditures are required from the remaining portions of a component for an interior paneling, it is customary to manufacture the component in several process steps, whereby oftentimes, the air bag area is first manufactured separately or together with the support for the plastic molding part and in a subsequent step, the component is finalized by applying additional layers and decorating layers, which fulfill the afore-described functions.
This type of manufacturing is not only very time consuming, but also requires high technical expenditures. In the past, it was always attempted to configure the area of the airbag cover of interior paneling components for motor vehicles in a simpler manner and with less expenditures yet without endangering the functionality of the air bag and without endangering the passengers in the vehicle.
In the DE 196 17 874 C2, the manufacture of an air bag cover for a dash board is described, wherein the dash board consists of a support layer and cover layer and the air bag cover is connected with the remaining area of the dash board via a hinge. The process is configured in such a way that the dash board with the air bag air bag cover is produced by injection molding in a single injection mold tool in several molding steps. Initially, the support layer is formed with the mold tool and subsequently provided with a cover layer in a second molding step. During manufacturing of the support, a gliding stamp fitted for the mold tool core is introduced into the cavity, in order to thus bring in openings in the area of the hinge. These hinge openings are provided as a passage for the soft resin injected in the second molding step, in order to form a strip at the rear side surface of the support in the area of the hinge, by means of which the hinge is strengthened and the air bag cover is held upon swinging open. The swinging open itself is facilitated by a rupture line which corresponds to the hinge. A disadvantage of this arrangement is that the airbag cover itself is coated only on one side which, according to experience, does not realize an optimal splinter protection. This disadvantage can be alleviated by adding another work step, in that in a separate mold tool at the rear surface of the air bag cover an additional splinter protection is placed by either gluing or by other means. However, this shows that the entire production will be considerably more expensive relative to cost and time.